1. Field of the Invention
The present invention relates generally to liquid crystal display (LCD) devices, and more particularly to color LCD devices for use with a touch-sensitive pointing input device and an image display method thereof.
2. Description of the Prior Art
Through the trend of complexity in computerization as to diversity of information in the recent past, portable or xe2x80x9chandheldxe2x80x9d electronic information management tools including personal digital assistants (PDAs) have found increasing applications due to advantages such as small size and light weight. In the thrust to achievement of such advanced handheld information management tools, the pen-input scheme is becoming more important for permission of direct entry of input data or instructions by use of a touch-sensitive coordinate pointing input device known as a xe2x80x9cpenxe2x80x9d pointer in the art through an associated tough-screen display panel in such a simple and easy way that allows users to xe2x80x9cwrite-downxe2x80x9d by hand on a memo pad. As such pen-input scheme, several techniques have been proposed until today, including a technique of laminating a pen-input panel (tablet panel) on an associated display panel, a technique of common use of a display panel also as the tablet, and others.
One typical pen-input scheme incorporating the former technique has been disclosed in, for example, Published Unexamined Japanese Patent Application (PUJPA) No. 58-200384 and also in PUJPA No. 7-175591. With the prior art, an input tablet is constituted from two light transmissive substrates having lateral and longitudinal elongate electrodes for position detection. The substrates may be made of glass, polycarbonate or other polymer material. When the pen pointer is manually operated by users to draw a desired locus thereon while rendering the pen pressed onto the surface of the tablet at a tip end thereof, a coordinate detector circuit operates to sense or detect corresponding coordinates of a drawing position every time the coordinates change. A control circuit is responsive to receipt of such detected coordinates for providing adequate image data indicative of character set or graphics as pursuant to the coordinate detection result, allowing a resultant drawing image to be visually indicated on the LCD panel under the control of LCD driver circuitry.
Unfortunately, the prior art LCD devices suffer from the lack of ability to process color images for display. A need has therefore been felt for a color-image displayable LCD device for use with the pen-pointer input device permitting direct entry of input data and instructions.
It is therefore an object of the present invention to provide a new and improved LCD display scheme capable of avoiding the problem as faced with the prior art.
It is another object of the invention to provide an improved color image displayable LCD device while permitting direct entry of necessary data or instructions by use of an associated touch-sensitive pointing input device.
It is yet another object of the invention to provide an improved method of displaying color images on LCD devices while permitting direct entry of input data or instructions using an associated touch-sensitive pointer.
To attain the foregoing objects, the present invention provides an LCD device having a display panel with an array of picture elements or xe2x80x9cpixelsxe2x80x9d organized into a matrix, capable of displaying an image as hand-drawn by use of a touch-sensitive pointing input device, featured in that the display device is arranged so that the image is displayable in more than one color thereon in response to operation of the pointing input device.
In accordance with another aspect of the instant invention, there is provided an LCD device including an LCD panel having an array of rows and columns of pixels defining a matrix, a position commander for determining a certain position for color display on the display panel, a coordinate detector for recognition of the certain position as determined by the commander and for generating and issuing an output signal indicative of a corresponding coordinate data, a color designator for designation of the kind of a color being selected for such color display, a memory device for storage of color data representative of the color as presently designated, a memory controller responsive to receipt of an address generated from the selected coordinate data for controlling the color data to be written into and read from the memory, and an output controller for allowing the color data read from the memory to be output onto the display panel as image data.
In accordance with still another aspect of the invention, the commander includes a pen-shaped touch-sensitive input device for use in drawing any desired locus being subject to color display on the display panel, while the coordinate detector includes a recognition function module for recognizing the locus drawn by the pen pointer thereby to provide an output being issued as X- and Y-coordinate data corresponding to the pixel dots on the display panel.
In accordance with a further aspect of the invention, the recognition function module may include a pressure sensor, an electrostatic sensor or a heat sensor.
In accordance with a yet further aspect of the invention, the color designator is comprised of a color designation area as provided in advance for a respective one of colors on the display panel permitting selection of any desired color in response to the commander. With the invention also, the color designator may be a color selection menu allowing the operation mode to be set in a color selection mode and permitting selection of a desired color through the color selection mode. The display panel may be of the active matrix type having thin-film transistors (TFTs) disposed at the pixels thereon.
In accordance with a still further aspect of the invention, there is provided a method for displaying a color image on an LCD panel with a matrix of rows and columns of pixels by using a pen-like touch-sensitive input device operatively associated therewith, which method includes the steps of designating a color to be displayed in advance, drawing on the display panel a locus being color-displayed by use of the pen pointer input device, providing the address of an associated data storage device based on the resulting coordinate data corresponding to the locus drawn, writing the selected color data into the storage device at the designated address thereof, and reading color data from the storage device thereby generating and issuing the same to the display panel as image data.
In accordance with the invention, the LCD panel has a matrix of rows and columns of pixels. To display a color image, a color designation means acts first to designate or determine the color to be displayed. This color designation may be performed by execution of pointing one of color designation areas each predefined for the individual color on a display panel; or alternatively, the same may be attained by setting the operation mode in a color selection mode through operation of a color selection menu.
Then, a position commander unit operates to instruct a specific position being subject to such color display on the display panel. More practically, the commander may be a touch-sensitive pointing input device, which is generally known as a xe2x80x9cpen pointerxe2x80x9d tool. This pen pointer is for use in drawing any desired line of locus to be color-displayed on the LCD panel screen. Each position designated by the commander is next recognized by a coordinate detector unit, which generates and issues corresponding coordinate data at an output thereof. The coordinate detector includes a recognizer for recognition of the locus as drawn or defined by movement of the pen pointer in such a way that the detector issues an output of recognizer as data indicative of X- and Y-coordinates corresponding to pixels or dots on the display panel. The recognizer here may be a pressure sensor, electrostatic sensor, heat sensor, or the like.
A storage controller unit is responsive to receipt of the resulting coordinate data for generating and issuing an address selected. Based on the address, the controller also serves to control read/write operations of color data with respect to a memory associated. The color data stored in the memory is then read out under the control of the storage controller to be supplied as video data to the display panel. In this way, it becomes possible to display a color image by use of pen input device.
These and other objects, features and advantages of the invention will be apparent from the following more particular description of one preferred embodiment of the invention, as illustrated in the accompanying drawings.